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FXUS63 KGRR 161929

Area Forecast Discussion
National Weather Service Grand Rapids MI
329 PM EDT Tue Jul 16 2019


Issued at 240 PM EDT Tue Jul 16 2019

- Locally heavy rainfall late this afternoon and early evening

- Risk for severe storms and locally heavy rain Thu into Fri

- Excessive heat looking likely for Thu into Sunday morning


.DISCUSSION...(This evening through next Tuesday)
Issued at 240 PM EDT Tue Jul 16 2019

The main weather challenges deal with the potential for
rain...severe weather and heat impacts through the period.

Late this afternoon and evening the atmosphere will remain very
moist with some instability. There will be some lift around as
well especially for the southeast half of the CWA. Thus very heavy
localized rainfall will fall and potentially lead to urban/poor
drainage issues. With the diurnal instability decreasing through should the strength of the showers.

Next up for active storms is Thursday into Friday. Stronger low
level jet is likely to interact with the instability across the
region leading to an MCS Wednesday night into Thursday morning.  
The instability persists through Friday along with the stronger
low level wind fields. So a risk for strong/svr storms and heavy
rain look elevated. In addition with the impressive 850 to 925 mb
temperatures...high heat index values are expected. Several days
of headlines for heat are likely needed.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 101 PM EDT Tue Jul 16 2019

Showers and even a few thunderstorms are forecasted for the
afternoon and evening as the atmosphere has become unstable.
Impacts are possible with local IFR and lower potential. Even
without the bases will occasionally fall into the
MVFR category.  

Tonight a risk for fog exists...mainly after midnight. That fog
should lift/dissipate around sunrise. Less potential for showers
exists for Wednesday.


Issued at 240 PM EDT Tue Jul 16 2019

No headlines for marine products needed at this time.




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